Stabilizing photographic emulsions with chloropalladites and chloroplatinites



Patented Aug. 28, 1951 ST'AEILIZING rnorrodngi nio iifMULfsi'oNs WITH CHLOROPALLADITES. AND" CHLORO- PLATiNITEs Adrian P. H. Trivelliand William-F. Smith-Rochester, N.;Y., assignors to Eastman Kodak Company, Rochester, N. Y., acorporation of New Jersey No Drawing. Applicationfiecmber 19, 1947,

Serial No. 7925842 7 4 Claims.

This invention relates to fog-inhibiting agents and stabilizers for photographic emulsions and to photographic emulsions containing them.

This application is a continuation-impart of our application Serial No. 687,239, filed July 30,

1946, now abandoned. It is known that photo-x graphic emulsions, particularly ultra-sensitive emulsions or those containing coloring serisitiz'ers exhibit a tendency to form a deposit of silver in the'emulsion. This deposit extendsmore' or less uniformly over the entire emulsion and is known as fog. Photographic fog is of two types: local and general. Local fog is formed by exposure of the film or plate at undesired points as by a little leak in the camera. General fog orasit is some- (ores-i) adverse conditions of temperature and humidity by the use of compounds of the formulas:

R'zMXi' and R3MX6 'in R is hydrogen or an 2.1km metai in cl'iiding" ammonium, M is'platinum or palladi M" is iridium or rhodium and is ahawgem Compounds suitable for use according" toour invention are those of :the abovegeneralformulas in which R is hydrogen or an alkali metal such as potassium or sodium, or ammonium; M

platinum or palladium; M is iridium or rhodium;

and X is a halogen atom such as chier nexor times known chemical fog is formed in a number of ways. It may be caused by the conditions under which the film or plate is stored, such as conditions of high temperature or humidity or unusually long time of storage; The" nature of the emulsion may also produce chemical fogas br'omirie; Suitable compounds are ammonium chloropalladite, (NH4)2(PdC14) ammonium chloroplatinite (NI-I4) zPtCli; ammonium chloroiridite 1 (NHLQBIICIQ and ammonium chlororhodite well as the conditions of development of the emulsion as by development for protracted periods of time or at temperatures above. normal. Highly sensitive emulsions are more likely to fog than those of lower sensitivity. wears primarily concerned with general or chemicaliog.

of silver halide emulsions at or close to initial optimum values under conditions of high temperature and humidity. Thefog inhibitors which we propose to use are added to the emulsion General fog and loss of sensitivity of the emulsion are especially likely occur when the sensitive material is stored under conditions other than ideal, that is, under conditions of high temperature and humidity as tropical regions.

It is an object of the invention to provide novel anti-fogging or fog-inhibiting compounds for emulsions. A further object is to provideantifogging agents which stabilize the initial sensitivity of the emulsion. A still further" object is to provide anti-fogging agents which improve the keeping of the emulsion in. tropical regions. Other objects will appear from the followingdescription of our invention.

In our prior application, Serial No. 765,818Lfi1ed August '2, 1947, We described the use as foginhibitors of compounds of the general formula:

of which ammonium ohloropalladate is aneuample. We have now foundthat the sensitivity d fog of nhotqgraphic mul iee may em mw tained at or'close to initial optimum values'under during" the process of manufacture to avoid-lossof sensitivityfand to inhibit' thef growth of chem'a-g ical fog withpassage of time under non-ideal con j ditioiis of storage. Theseconditions freque exist where photographic emulsionsare' used tropical countries or on naval vessels or manufacturing plafits'wlie're adverse keeping conditions" prevail. The advantages of our discovery reside a widerange of climatic conditions.

A solution of ammonium chlorop-alladite or a other fog inhibitor used according to our invention, when added in suitable concentration lie" 40.

unsensitized or optically sensitized photograph emulsions before coating, does not eifecttlie sen-Q sitometric values for sensitivity and fog when.

measurements are made soon after coating.

When sensitcmetric masurements are mad}; after appreeiame intervals of time under tropical 6r dry conditions or storage at elevated tempera:

tures, however, these compounds do" stabilize plie tcgraphic speed andina'i'ntain reg at a' iewiev The preparation of s'iwr halide exams-ion in volves three separate operations (l') theemulsiii By the use of the compounds oi our invention, it is possible to maintain the sensitivity and fog.

3 cation and digestion or ripening of the silver halide, (2) the freeing of the emulsion from excess soluble salts, usually by washing, and (3) the second digestion or after-ripening to obtain in- The fog inhibiting agents which we have described may be used in various kinds of photographic emulsions. In addition to being useful in ordinary non-sensitized emulsions, they may also creased e v y e y Of the 5 be used in ortho-chromatic, panchromatic and Photographic P 1912)- We prefer to add X-ray emulsions. If used with sensitizing dyes, h f nhi n mp n af r the final they may be added to the emulsion before or digestion after-ripening, although they may after the dyes are added. Various silver salts may be added prior to the fin e p- Useful be used as the-sensitive salt, such as silver broconcentrations are from 0.25 to .9 gram o o mide, silver iodide, silver chloride and mixtures inhibitor per kilogram of silver nitrate converted of t Th dispersing agents may be gelatin to Silver halide in ma t emlllSiOIl- "or other colloid, such as collodion, alubumen, The fog inhibiting d Stabilizing action of 0111 cellulose organic derivatives or synthetic resins. compounds was determined by incubation of the t 1 be understood t t we contemplate as emulsions with simulated tropical conditions an 5 included within our invention all modifications also y incubation in dry heat at and equivalents falling Within the scope of the apous lengths of time from 12 days to 2 months. pended 1 The results of these tests are tabulated below and w claim; are compared with the initial Speed, gamma and 1. A stabilized silver halide emulsion containfog of the emulsions with and Withou? the Stabi' ing silver halide as the sole sensitive ingredient 112mg compounfi- The tests from Whlcl} the and containing from 0.25 gram to 3.9 grams per IOWmg tabulatlon was made used a hlgh'speed kilogram of silver nitrate converted to silver negative silver halide emulslon exposed on an halide in making the emulsion, f a compound Eastman type IIB sensitometer and developed for having the Structure five minutes in a developer of the following composition: R2MX4 Grams where R is selected from the group consisting of Monomethyl paramtnophenol Sulfate ydrogen, alkali metals and ammonium, M is sesodium White (desmcated) 30 lected from the group consisting of platinum and g i 3 palladium and X is a halogen atom. gg i g z i gfi g 0 5 2. A. stabilized gelatino-silver halide emulsion Water to one liter containing sliver halide as the sole sensitive ingredient and containing from 0.25 gram to 3.9 The results are as follows: grams per kilogram of silver nitrate converted to Routine 12 da. at 120 F. 8 wks. Tropical V (N HdlalPdgh grams g. g ig 5 Gamma Fog ig Gamma Fog ig Gamma Fog Routine 12 da. at 120 F 8 wks Tropical (NHmPtghfigroam PM g a ig Q Gamma Fog ig 5 Gamma Fog i g Gamma Fog Routine 12 (is. at 120 F 8 wks Tropical (N H1) QIIOIQ gram per kg'AgN ig Gamma Fog ig h Gamma Fog ig Gamma Fog None 710 1.48 .08 300 1.51 is 193 1.34 .41 .434 890 1.35 .10 575 1.29 .20 198 1,40 .30 1,380 1.17 .11 490 1.33 .22 218 1. 39 .31 935 1.35 .10 535 1.30 20 210 1. 30 .30 370 1.39 .09 343 1.40 19 153 1.37 .52

The fog inhibiting agents of our invention are useful principally with emulsions which are desflverhhahde m gmkmg the emulslon' of ammom' veloped with organic developing agents not conum c taining metals. Such developing agents are hygelatmo'snver hahde 82311151011 droquinone, para aminophenol and its deriva containing silver halide as the sole sensitive intives, pyrogallol, paraphenylenediamine and its gredlent and 00111121111112 from gram to 3.9 derivatives, phenylhydroxylamine, etc. grams per kilogram of silver nitrate converted to silver halide in making the emulsion, of ammonium chloroplatinite.

4. The method of stabilizing the speed and reducing the amount of fog produced upon development of a silver halide emulsion containingisilver halide as the sole sensitive ingredient, which comprises incorporating in said emulsion from 0.25 gram to 3.9 grams per kilogram of silver nitrate converted to silver halide in making the emulsion, of a compound having the structure where X is a halogen atom, R is selected from the group consisting of hydrogen, alkali metals and ammonium, and M is selected from the group 15 1,120,580

. 6 consisting of platinum and palladium, and developing said emulsion after exposure with an organic developing agent free of a metallic element.

ADRIAN P. H. TRIVELLI. WILLIAM F. SMITH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number I Name Date 1,120,429 Willis Dec. 8, 1914 Willis Dec. :8, 1914 

1. A STABILIZED SILVER HALIDE EMULSION CONTAINING SILVER HALIDE AS THE SOLE SENSITIVE INGREDIENT AND CONTAINING FROM 2.25 GRAM TO 3.9 GRAMS PER KILOGRAM OF SILVER NITRATE CONVERTED TO SILVER HALIDE IN MAKING THE EMULSION, OF A COMPOUND HAVING THE STRUCTURE 